I wrote a small History API (History.as and HistoryEvent.as) that I'd like to share on this forum with anyone that might find it useful for their BlackBerry® PlayBook™ applications. Fill your boots!
Basically, it allows you to record property values of objects to a history stack which can be undone and redone. I've attached a "HistoryTest" example project that demonstrates the use of QNX LabelButtons ("Undo" and "Redo") to undo and redo changes of a draggable sprite and/or a QNX Slider object.
I'm also very open to receive some suggestions, thoughts on if / how the code (History.as and HistoryEvent.as) can be refactored, optimized or broadened. I'm all ears.